The Interstate Highways serving Baltimore are I-70, I-83 (the Jones Falls Expressway), I-95 (the John F. Kennedy Memorial Highway), I-395, I-695 (the Baltimore Beltway), I-795 (the Northwest Expressway), I-895 (the Harbor Tunnel Thruway), and I-97. Several of the city's Interstate Highways, e.g. I-95, I-83, and I-70 are not directly connected to each other, and in the case of I-70 end at a park and ride lot just inside the city limits, because of freeway revolts in the City of Baltimore. These revolts were led primarily by Barbara Mikulski, now a United States Senator, which resulted in the abandonment of the original plan. U.S. highways and state routes that run to and through downtown Baltimore include US 1, US 40 National Road, and the Baltimore-Washington Parkway. There are two tunnels traversing the Baltimore harbor within the city limits: the four-bore Fort McHenry Tunnel (served by I-95) and the two-bore Harbor Tunnel (served by I-895). The Baltimore Beltway crosses south of Baltimore harbor over the Francis Scott Key Bridge.
Baltimore is a top destination for Amtrak along the Northeast Corridor. Baltimore's Penn Station is one of the busiest in the country. In FY 2008, it ranked 8th in the United States with a total ridership of 1,020,304. Just outside the city, Baltimore/Washington International (BWI) Thurgood Marshall Airport Rail Station is another popular stop. Amtrak's Acela Express, Palmetto, Carolinian, Silver Star, Silver Meteor, Vermonter, Crescent, and Northeast Regional trains are the scheduled passenger train services that stop in the city. Additionally, MARC commuter rail service connects the city's two main intercity rail stations, Camden Station and Penn Station, with Washington, D.C.'s Union Station as well as stops in between.

Interior of Baltimore-Washington International Thurgood Marshall Airport, Baltimore's major commercial airport
Public transit in Baltimore is provided by the Maryland Transit Administration. The city has a comprehensive bus network, a small light rail network connecting Hunt Valley in the north to BWI airport and Cromwell in the south, and a subway line between Owings Mills and Johns Hopkins Hospital. A proposed bus rapid transit or rail line, known as the Red Line, which would link the Social Security Administration to Fells Point and perhaps the Canton and Dundalk communities, is under study as of 2007; a proposal to extend Baltimore's existing subway line to Morgan State University, known as the Green Line, is in the planning stage.
Baltimore is served by Baltimore-Washington International Thurgood Marshall Airport, generally known as "BWI," which lies about 10 miles (16 km) to the south in neighboring Anne Arundel County, and by Martin State Airport, a general aviation facility, to the north in Baltimore County. BWI and Martin State airports are operated by the Maryland Aviation Administration, which is part of the Maryland Department of Transportation In terms of passenger traffic, BWI is the 24th busiest airport in the United States. Downtown Baltimore is connected to BWI by two major highways (I-95 and the Baltimore-Washington Parkway via Interstate 195), the Baltimore Light Rail, and Amtrak and MARC commuter rail service between Baltimore's Penn Station and BWI Rail Station. Martin State Airport is linked to downtown Baltimore by two major highways, I-95 and U.S. Route 40, and MARC commuter rail service between Baltimore's Penn Station and its nearby Martin State Airport MARC Train stop.